Under the Food Safety Modernization Act (FSMA), food manufacturers are charged with employing processes that mitigate risks and aid in the delivery of safe and stable products. Manufacturers employ a wide range of thermal processes to inactivate spoilage microorganisms and pathogens that can affect product shelf-life. Verifying the effectiveness of these processes through well-designed and executed validation studies is essential in today’s regulatory environment. 

To validate the inactivation of spoilage organisms or bacterial pathogens during the cooking step, there are generally four approaches to consider for food process validation studies. As presented below, they can be simple or complex based on how much information is needed or desired:

  • Log Reduction
    The basic approach is to inoculate product, subject it to heat at a fixed temperature for a fixed time, followed by enumeration of the inoculum before and after heating. The difference between the before and after counts, when expressed as a log base 10 value, is the log reduction obtained by your process.
  • D-value
    The next level of study complexity is the determination of the D-value, where D represents the decimal (log) reduction in counts. This determination is conducted at a fixed temperature for different lengths of time. The advantage of this approach is that you will know the degree of inactivation at your process temperature for any length of time.
  • Z-value
    The highest level of study is the determination of D-values at multiple temperatures to arrive at a z-value. The advantage of this determination is predictability of lethality (log-reductions, Fo) for any heating profile covered by the temperature range of the study.
  • In-Plant Using a Surrogate    
    Process validation studies conducted in production plants or pilot plants are recommended when the process is difficult to mimic in the laboratory. Surrogate organisms are selected representing a greater heat resistance than the desired target (i.e., Salmonella). Surrogates are prepared in the laboratory, shipped to the plant, and product is inoculated on-site. Product containing inoculum is enumerated before and after the process. The difference between the before and after counts, when expressed as a log base 10 value, is the log reduction obtained by your process.

With years of experience, the Silliker Food Science Center can design and conduct process validation studies to meet your business needs. Whether a study is conducted in the laboratory or a plant, we provide data to support informed decisions about the quality and safety of products.

Click here to read our related blog article “Food Process Validation: At Home and Abroad

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